Breathing apparatus



Nov. 24 1959 P. MEIDENBAUER, JR 2,914, 67

1 BREATHING APPARATUS Filed March 1. 1954 INVENTOR, 22/ PHILLIP E. MEIDENBAUEVRJR. DECEASED, BY LOIS w. MEIDENBAUER,EXECUTR!X' n td ws lic This invention relates to breathing apparatus and more particularly to apparatus providingv a mixture of relatively effective and relatively inefie ctiye gases, examples of such contrasting, gases being oxygen contrasted with air and oxygen contrasted vwith the productsof exhalation of the user. While an; important -,feature is to supply an aviator with air or hisexhalation; products enriched with the quantity of oxygen required at different altitudes, the apparatusof the present invention is also useful in therapeutic work for supplying the desired proportion of oxygen or othenrelatively efi'ective gases ingrelatively ineifective gases enriched with such relatively effective gases. s g

This application is a continuation in part of my copending. application, Serial No. 322,842 filed November 28, 1952, now Patent No. 2,766,752yfor Methodjand Apparatus for Supplying Gasfor Respiration.

One of ,theprincipal objects of the present invention 7 is to provide apparatus for enriching gases being inhaled with a relatively effective, gas in which the'proportion of relatively eifective gas, under-any ambient condition can be setwith a-;highndegre e ofaccuracy. L t 1 Another most importantobject isto providesueh apparatus which will supplyan aviator with the quantity of oxygen required at different altitudes, the proportion of oxygen required .by the aviator increasing with increase'. in the altitude. t t-f Another object is to provide 'suchpapparatus' which, above a predetermined altitude, will.supply .o'xygen substantially exclusivelytothe aviaton. f

Another object is toprovide. such apparatus in which moderately high pressure relatively effective gasis applied to the breathing regulating mechanism, .thus insuring that any leakage is to the exteriorto-avoid contamination of the gas; permitting the use of smaller: and less bulky lines; and in particular permitting the employment -of the line to such breathing regulating mechanism as :.a small volume demand storage chamber in which succes :sive charges of the relatively effective gas can be accumulated.

Another aim is to provide suchiapparatus which in corporates simple valve mechanisms which are .of such zfil lfiii? Patented Nov. 24, 1959 2 effective gas and ambient air as the relatively ineffective gas.

Fig. 2 is an enlarged elevational view taken generally on line 2--2, Fig. l, and showing the parts broken away to disclose the mechanism.

Fig 3 is a fragmentary section taken generally on line 33, Fig. 2. 1

Fig. 4 is an enlarged fragmentary sectional view taken generally on line 4-4, Fig. i 1. V

' Fig. 5 is a longitudinal section through the aneroid valve shown in Fig. 1.

In the form ofthe invention illustrated the numeral ltlrepresents an oxygen storage cylinder containing substantially pure oxygen at a higher pressure of, say, 2,000 p.s.i. To the outlet neck of this oxygen cylinder is screwed a regulator or reducing valve 11 shown as having a gage 12 which indicates the pressure within the oxygen storage tank It) and also shown as having a gage 13 indicating the pressure on the outlet side of the regulator or pressure reducing valve 11 and which pressure can be any value up to 100 p.s.i., say, a constant absolute valve of 50 psi.

The outlet tube 14 from the regulator or pressure reducing valve 11 is shown as clamped against a screw fitting or nipple 15 by means of a threaded collar 16, as best shown in Fig. 4. The other side of the fitting or nipple 15 is connected by a line 18 with a breathing mechanism indicated generally at 20.

An important feature of the invention resides in the provision of a restricted orifice 2 1 through the fitting ornipple- 15 and which orifice provides a medium pressure demandstorage chamber 22 in the line 1% connecting the fitting 15' with the breathing regulating mechanism 20. A feature. of the invention is in its automatic conversion at a predetermined altitude into a demand reg:

ulated breathing apparatus for supplying substantially 21 under control of an aneroid valve, and for this purpose a bypass line 23 is provided around this orifice and which contains an on-off valve 24. In addition, this bypass line can contain an aneroid valve 25. The aneroid valvecan be of any suitable construction but is shown as comprising a valve housing 26 having an integral partition'27 with a valve opening surroundedby a transversely facing valve seat 28. A valve head 29 engages this valve seat 28 and is fixed to a valve stem 30,.sliding in a gland 31 in the side wall of the casing 26. The aneroid valve includes a sealed bellows 32 having a corrugated cylindrical side wall and end heads one of which end heads is connected with the outer end of the valve stem 30. The other end head is connected with a U-shaped bracket 33 the ends of which are suitably fastened to the exterior of the valve housing 26. The internal pressure in the bellows 32 can be of any value,

. say, to open the valve head 29 when the apparatus apparent from the'following description and drawings in which: V

Fig. l is a fragmentary'elevational viewof apparatus embodying the presntinventionjand shown as particularly' designed for "supplying oxygenas" the relatively reaches an altitude of 20,000 feet.

The breathing mechanism 20 is shown as including a generally cylindrical metal shell 35 having a circular rim 36 and, across one side, a wall 38 forming the side'of a relatively large demand chamber 41 within the shell 35. At one side the shell 35 is provided with an integral inlet neck 42 which is shown as projecting radially from the rim 36 and as connected with the end of the line 18 and hence is in communication with the medium pressure demand storage chamber 22 .formed by this line 18. s a

The bore 43 through the neck 42 communicates with the stem of a pressure gage flow indicator 44. Such a flow indicator preferably includes a vane which is moved in response to variations in pressure and since the pressure in the medium pressure demand storage chamber 22 varies substantially from zero to full medium pressure on each inhalation, this gage or flow indicator 44 can be of rugged construction, its primary purpose being to show to others that the user is breathing normally and that the apparatus is functioning properly with oxygen being supplied from the storage tank 10.

The bore 43 in the inlet neck 42 is provided with an angular portion 45 which opens toward the demand chamber 41 and has its axis directed toward the center of a circular plate 46 secured to the inner face of a diaphragm 47. The rim of this diaphragm embraces a bead 43 on the rim 36 of the shell 35, this diaphragmthereby form.- ing one wall of the demand chamber 41 and enclosing this chamber. The rim of the diaphragm 47 is secured to the head 48 of the shell 35 by a cover 49 having a rim 50 which embraces the rim of the diaphragm 47. A chamber 51 is thereby formed between the diaphragm 47 and the cover 49 and an ambient pressure is maintained in this chamber 51 by the provision of vent openings 52. If it is desired to maintain a slightly higher than ambient pressure in the demand chamber 41 so that any leakage will be to the exterior of the apparatus, a light compression spring (not shown) can be interposed between this diaphragm and the cover 49 as illustrated in detail in my copending patent application forContrbl Device for Breathing Apparatus, Serial No. 313,867, filed October 9, 1952, now Patent No. 2,728,340.

The angular portion 45 f the bore 43 in the inlet neck 42 carries a demand valve 55 and is shown as being enlarged to provide an annular shoulder 56 opposing the demand chamber 41. A metal valve seat disk 58 'is press fitted in the angular portion 45 of the bore 43 against the annular shoulder 56. This valve seat disk 7 has a central opening 60 which is preferably of conical form enlarging and with its axis directed toward the center of the metal plate 46 and diaphragm 47. The valve head 61 of the demand valve 55 is shown as being in the form of a cup with an axially extending rim 62 fitted on the face of the valve seat disk 58 remote from the demand chamber 41. In this valve head is anchored one end of a valve stem or rod 63 which projects through the opening 60 of the valve seat disk and has a rounded end 64 arranged in close proximity to the center'of the metal disk 46 mounted on the diaphragm 4'7. The demand valve 55 is also shown as having a return spring 65. This spring biases the valve head 61 toward its closed position. This spring is shown as being in the form of a spiral compression spring with its large end bearing against the valve seat disk 58 and with its small end bearing against a small collar 66 press fitted on the rod 63.

The shell is shown as provided with an outlet neck 67 which is shown as projecting radially from the rim 36 opposite from the inlet neck 42. This outlet neck 67 provides communication between the demand chamber 41 and the mask 68 of the wearer, the connection between the outlet neck 67 and the mask 68 being shown At ground level it is desirable that the demand valve 55 open slightly in advance of or contemporaneously with the check valve 73, the strength of the spring 74 being so selected. Accordingly the oxygen stored under pressure in the reservoir 22 is available before or along with the opening of the check valve 73. At higher elevations with correspondingly reduced ambient pressures and corresponding reduced pressures in the demand chamber 41 while only the same weight of oxygen may be available under pressure in the reservoir 22, this oxygen expands to an increased volume of gas which precedes or enters with the ambient air entering past check valve 73. As higher altitudes and lower ambient pressures are encountered, the check valve 73 stays closed for an increasingly longer time or opens for a shorter time because of the availabilityof the oxygen under pressure from the storage chamber 22 progressively increasing volume at the corresponding decreasing pressures in the demand chamber 41.

In the following description of the operation, it will be assumed that the mask 68 is applied to the face of the user; that the storage cylinder 10 contains oxygen underpressure of 2,000 p.s.i. as indicated on the gage 12; that the outlet pressure of theregulator or pressure reducing valve 11 is a constant 50 p.s.i. as indicated on the gage 13; and that the manual bypass valve 24 is closed so that this pressure of 50 p.s.i. is applied to the orifice 21 and so that oxygen at this pressure builds up in the medium pressure-demandstorage chamber 22 at a rate corresponding to the size of the orifice 21 which will be assumed to be of such size as to pass five liters per minute (hereinafter abbreviated l.p.m.) at the assumed 50 p.s.i. pressure. This 5 l.p.m. at 50 p.s.i. builds up in the reservoir 22 and upon being released into the demand chamber 41 expands, of course, to a greater number of liters due to the reduced pressure in the demand chamber. The substantially constant flow of oxygen through the orifice 21 is. a function or the assumed inlet pressure of 50 p.s.i. because this pressure, in the regular use of the apparatus, is above the critical ratio, that is, so far exceeds the close to ambient pressure in the demand chamber 41 and periodically opened reser- 'voir 22, that the rate of flow is determined by the high mined by the pressure drop across the orifice but by the as being in the form' of a flexible tube 69. The mask 1 68 is shown as provided with a conventional outwardly openlng exhaust check valve 70- through which the user exhales on each exhalation. The wall 38 of the sheet metal shell 35 is provided at its center with one or more openings 71 adapted to establish communication between the demand chamber 41 and the atmosphere. These openings 71 are surrounded by anannular bead 72 which PIOJCClZS into the demand chamber41 and forms a seat for a thin metal valve disk '73 which is biased into its closed position against the bead 72 bya spiral compression spring 74. The large end of this compression spring 74 bears against the face of the metal valve disk 73 and its small end bears against an L-shaped bracket 75' secured to-the inner face of the wall 38 as by screws 76 and havingan extension 78 which alines with the openings 71 and against which the small end or the spiral compresslon spring 74 bears. V

inlet pressure. It will also be assumed that the masl: is being used by an aviator starting out at'ground level or zero feet elevationand rising to an elevation of 33,000 feet while inhaling at a rate of 20 l.p.m. When the user, wearing the mask 68, inhales, through the flexible conduit 69 and outlet neck 67, a negative pressure is established in the demand chamber 41. This negative pressure performs two functions, that is, it moves the diaphragm 47 to the right as viewed in Fig. 3 and also moves the disk of the check valve 73 to the left as viewed in this'figure against the resistance of its spring 74. Even at ground level'the demandvalve 55 is preferably more sensitive to negative pressures due to inhalations of the user in the demand chamber 41 than the check valve 73 and at'higher altitudes, because of the increasing expansion of the oxygen from 22 and hence increased volume of this expanded oxygen, the opening of th ambient air valve 73 is increasingly delayed as higher altitudes are reached. With the opening of the check valve 73 ambient air at ground level pressure flows through the openings 71 into the demand chamber 41 and is thence drawn into the lungs of the user. At the same time the movement of the diaphragm 47 causes this diaphragm to contact and move the free end 64 of the valve stem (a rod 63 laterally to the right. This tips thecup shaped valve head 61 laterally and hence separa e i of it bead 62 from the hig Pr r d ofthe valve seat disk 58 landmermits; the charge of medium pressure gas'in the medium pressure demand storage chamber 22 to escape through the valve opening 60 into the demand chamber 41; The inhalation of the user continues after the supply of oxygengstored in the demand storage chamber 22 has beenrusedup following which oxygen is supplied to the user at the rate determined by the size of the restricted orifice 2 1 and the high inlet pressure, this rate being assumed to be 5 l.p.m. and this inlet pressure being assumed to be .50 p.s.i. While oxygen at this rate isbeing so delivered through the demand chamber 41 to the lungs of the user ambient air is also being delivered through/the openings 71 and demand chamber 41 to the lungs of the user so that a mixture of oxygen and ambient air is supplied to theuser. At ground level, with an orifice 21 flow of 5 l.p.m. and at the assumed inhalation rate of the user of 20 l.p.m., the gas drawn into thelungs of the user would be approximately 25%. oxygen and 75% ambient As the airplane rises to an elevation, .of say, 18,000 feet the ambient air pressure reduces whereas the assuined pressure of the oxygen and its. rate of flow through the restricted orifice 21 remains the same; FAccordingly at such higher altitude there necessarily is a proportionally greater flow of oxygen through the restricted orifice '21 and past the demand valve 55 into the demand chamber 41 on each inhalation than there is ambient air through the opening 71,into the demand chamber 41. This is due to the fact that the assumed 5 l.p.rn. of oxygen at 50 p.s.i. expands to a larger volume on entering the demand chamber 41 and this larger volume of oxygen is withdrawn by the user before the ambient air valve 73 opens. The operation of the apparatus is exactly the same as just previously described except that the lowering of the ambient pressure while maintaining a constant oxygen pressure and size of the orifice21 provides a greater proportion in volume of expended oxygen, in the mixture drawn into the lungs ofthe user. ,At 18,000 feet the gas drawn into the lungsof, the user; would be 50% oxygen and 50% ambient air. T

As the airplane continues to gain elevation the ambient air pressure continues todrop and sincethe pressure of the oxygen and size of'the. orifice 21. remain constant there will be ,a still greater increase in the volume of oxygen. drawn into the lungs .of the user as compared with the amount of ambientaairQ With an inhalation, rate of 20 l.p.m., and an orificesize to deliver 5 1.p.m.

of oxygen at, 50 psi. to;.the demandvalve 55, at 33,000 feet the'user would be breathing pure oxygen since with the corresponding ambient pressure and; at this inhalation rate the valve disk 73 would notbe opened at all, ade-' quate oxygen being supplied from the open. aneroid valve 25. 'The following is atable showing the percent of oxygen added to the gas drawn into the lungs of-the user at dilterent altitudes and at different inhalation: rates of the user both with the size of the orifice 21 proporthe exhaust check valve'170 so that,.theusers'products-of exhalation are exhausted directly to the atmosphere. The invention, however'comprehends the use of such products of exhalation as the relatively ineffective gas, that is, in lieu of ambient oxygen.

If desired, the manual on-ofi valve 24 can be opened. When this is done the operationof the apparatus is exactly the same as that previously described up to the time that. the airplane reaches the altitude at' which the aneroid valve 25 has been set to open. When this altitude is reached the reducing ambient pressure on the bellows 32 causes its internal pressure to expand the bellows and move the valve head 29 away from the valve seat 28. Accordingly oxygen, at the assumed pressure of 3 atmospheres, is bypassed around the orifice 21 and is available at this pressure at an unlimited rate since the rate of delivery of the demand valve 55 with an unrestricted supply, of oxygen exceeds the maximum inhalation rate of the user. Since .there is no restriction to the amount of oxygen drawn into the lungs of the user and since the aneroid valve 25'would only open at a relatively high altitude, on each inhalation of the user only pure oxygen would be drawn into. the lungs ofthe user.

tioned to deliver 5 l.p.m. ofoxygen and l0'-l-.p.m. of

oxygen. From this table it will be seen-that at higher than 'ground level the, say 5 l.p.m., released by the orifice at 50 p.s.i. expands to a greater volume and which is measured in altitude l.p.m.

When the user exhales a positive pressure is established in the mask 68 and this positive pressure opens delivers such substantially pure oxygen. It will also be seen that the apparatus .is very compact, this particularly. resulting from the'useof medium pressure in supplying the oxygen to the control apparatus.

'Iclaim:

1. Apparatus for separately supplying relatively effective and relatively ineifective gases for respiration, which comprises means forming a demand chamber adapted to be placed in communication with the respiratory passages leading to the lungs of the user, means arranged to supply to said demand chamber said relatively ineffective gas, a check valve interposed betweensaid last means and said demand chamber and opening toward-said demand chamber in response to negative "pressures in said demand chamber created by the inspiration demands of the user, means arranged to supply to said demand chamber said relatively efiective gas under higher pressure than said relatively ineffective gas, means providing an orifice restricting the fiow of said relatively effective gasto such degree that at higher pressures 'of said relatively ineffective gas both said relatively efiective and relatively ineffective gases are supplied to said demand'chamber, a

bypass line around said means providing said orifice, a'

manual valve arranged in said bypass line, a demand valve controlling the flow of said 'relativ'ely effective gas from said supply means to said demand chamber, and means responsiveto the inspiration demand of the user and arranged to actuate said' demand valve to admit saidhigher pressure relatively effective gas to said'de'mand chamber.

2. Apparatus for separately supplying relatively effective and relatively ineffective gases for respiration, which comprises means forming a demand chamber adapted to be placed in communication with the respiratory pas sages leading to the lungs of the user, means arranged to supply to said demand chamber said relatively ineffective gas, a check valve interposed between said last means and said demand chamber and opening toward said demand chamber in response to negative pressures in said demand chamber created by the inspiration demands of the user,.

means arranged to. supply to said demand chamber said relatively effective gas under higher pressure than said relatively inelfective gas, meansproviding an orifice restricting the. flow of's'aicl relatively effective gas to such degree that at higher pressures of said relatively ineffec-- tive gas both said relatively effective and relatively ineffective gases are supplied to said demand chamber, a bypass line around said means providing said orifice, an aneroid valve arranged in said bypass line and opening said bypass line in response to a fall in pressure of said relatively ineffective gas below apredetermined level, a demand valve controlling the flow of said relatively effective gas from said supply means to said demand chamber, and means responsive to the inspiration demand of the user and arranged to. actuate said demand valve to admit said higher pressure relatively'ettective gas to said demand chamber. v

3. Apparatus as set forth in claim 2 wherein a manual valve is also included'in said bypass line.

,4. Apparatus as set forth in claim 2 wherein said relatively efiectiv'e gas. is oxygen and wherein said relatively ineffective gas is ambient air.

5. Apparatus. for separately supplying relatively efiective and relatively ineffective gases for respiration, which comprises means forming a demand chamber adapted to be placed in communication with the respiratory passages leading, to the lungs. of the user, means arranged to supply to said demand chamber said relatively inelfective gas, a check valve interposed between said last means and said demand chamber and opening toward said demand chamber in responseto negative pressures in said demand chamber created. by the inspiration demands of the user, means forming a demand storage chamber adjacent said demand chamben'means arranged to refill said demand storage chamber with saidv relatively eifective gas at a pressure higher than, said relatively ineffective gas, means providing an orifice restricting the flow of said relatively effective gas, to, such degree that at higher pressures of said relatively ineffective. gas both said relatively effective and relatively ineffective gases are supplied to said demand chamber, a bypassline around said means providing said orifice, a manual valve arranged in said bypass line, a demand; valve between said demand chamber and said demand storage. chamber, and means responsive to the inspiration demand of the user and arranged to actuate said, demand valve to establish communication between said demand. chamber and said demand storage chamber.

6. Apparatus for separately supplying relatively effective and relatively ineffective gases for respiration, which comprises means forming a demand chamber adapted to be placed in communication with the respiratory passages leading to the lungs of the user, means arranged to s pply to said demand. chamber said relatively ineflective gas, a check valve interposed between said last means and said demand.. chamb,er and opening toward said demand chamber in response to negative pressures in said demand chamber created by the inspiration demands of the user, means forming a demand storage chamber adjacent said demand chamber, means arranged to refill said demand storage chamber with said relatively effective gas at a pressure higher than said relatively inefiective gas, means providing an, orifice restricting the flow of said relatively effective gas to such degree that at 8 higher pressures of said'relatively inelfective g'as both said relatively effective and relatively ineffective gases are supplied to' saiddemand "chamber, a bypass linearound said means'providin'g'said orifice,an aneroid valve arranged in said bypass 'line and opening saidbypass line in'response to a fallin pressure of said relatively ineffective gas below a" predetermined level, a demand valve between said demand chamber and said demand storage chamber, andmeahsresponsive to the inspiration demand of the user and arranged to actuate said demand valve to establish communication between said demand chamber and said demand storage chamber.

7. Apparatus as set forth in claim 6 where a manual valve is also included in said bypass line.

8. Apparatus as s'et'forth' in claim 6 wherein said rela-' tively effective gas is oxygen and said relatively ineffective gas is ambientair. i

9. Apparatus for'separately supplying relatively effective and relativelyineffective gases for respiration, which comprises a mask adapted to be placed over the face of the user with its interior chamber in communication with the respiratory passages leadingto the lungs of the user, means arranged to provide a demand chamber, conduit means establishing communication between the interior" of said mask and said demand chamber and through which said effective and ineffective gases are supplied for breathing from 'said demand chamber to the interior of; said mask and through which the negative pressures in said mask created by the inspiration demands of the user are transmitted to; said demand chamber, means arranged to supply to said demand chamber said relatively ineffective gas, a check valve interposed between said last means and said demand chamber and opening toward said demand chamber in response "to said negative pressures in 'said demand chamber created by the inspiration demands' of the usefn'means arranged to supply to said demand chamber saidrelatively effective gas under higher pressure than said relatively ineffective gas, means providing an orifice re'stricting the flow of said relatively effective gas through said last means to such degree that at higher pressures of said relatively ineffective gas both said relatively effective and relatively ineffective gases are supplied to said demand chamber, a demand valve controlling the flow of said relatively effective gas from said supply means to said demand chamber, and means responsive to -said negative pressures in said demand chamber created by the inspiration demands of the user and actuating saiddemand valve to admit said higher pressure relatively effective gas to said demand chamber.

References Cited the file of this patent UNITED STATES PATENTS 2,220,368 Heidbrink Nov. 5, 1940 2,378,047 Strange June 12, 1945- 2,396,716 Meidenbauer Mar. 19, 1946 2,436,522 Meidenbauer Feb. 24, 1948 2,449,548 Burns Sept. 21, 1948 2,597,039 Seeler May 20, 1952 2,608,200 Stockman' Aug. 26, 1952' FOREIGN PATENTS 1 439,183 Great Britain 1935 500,789 Great Britain 1939 

